A conventional mobile network may be composed of a voice network component and a signaling network component. The voice component may include one or more trunk lines divided into several bearer channels capable of transmitting voice data (i.e. calls) for a relatively small number of subscribers. For example, a single voice trunk may be only capable of carrying 32 channels simultaneously. As used herein, the term “voice resources” refers to the resources in the network that carry voice data.
In contrast, the signaling component of a mobile network may be capable of serving a relatively large number of subscribers. For example, a single signaling communications link may be capable of serving up to 50,000 subscribers, including call setup, call teardown, and other call maintenance modules. Additionally, the signaling network may be utilized for performing modules other than call setup and teardown, such as the delivery of simple message service (SMS) messages, multimedia message service (MMS) messages, or providing number portability (NP) functionality. The signaling network may also include one or more signaling nodes for managing the allocation of voice resources for mobile users. Therefore, voice resources are typically scarce in comparison to signaling resources in mobile communications networks.
During conventional operation, registration in a mobile network is open to any mobile user. For example, when a mobile user activates his or her mobile handset, the handset may automatically register with the mobile network in order to provide availability and location information to the mobile network. Upon registration, mobile users may place calls on a first-come, first-served basis. For example, a calling party may initiate a call to a called party by dialing a subscriber identifier associated with the called party into his or her handset. One or more signaling messages may then be exchanged between signaling nodes in order to setup the call which may include allocating voice resources. After voice resources are allocated, the call may be maintained until one of the parties initiates call teardown. For example, call teardown may be initiated when a party sends a signal from his or her handset (i.e. hangs up) and signaling messages may again be exchanged between signaling nodes so that voice resources may be released for use in another call.
An important assumption of conventional mobile network operation is that only a small percentage of registered users place calls simultaneously. Therefore, a larger number of users may be registered in the signaling component of the network than the voice component is capable of processing. For example, one million subscribers may be registered in a mobile network serving Raleigh, N.C. However, only one thousand calls may need to be connected and maintained simultaneously at any given time. Therefore, an implicit assumption of the mobile network is that no more than one percent of registered users will require access to voice resources at a given time.
One problem associated with conventional mobile networks is that high priority users may not have access to voice resources during an emergency or other high traffic event. For example, during an emergency (i.e., earthquake, tsunami, terrorist attack, etc.), a dramatic increase in the number of users placing mobile calls occurs. Some users may attempt to call loved ones, other users may be attempting to coordinate emergency services, while yet other users may be unaware of the emergency and be placing non-essential calls. During this time period, the number of call setup requests increases beyond the voice capacity of the voice network to handle it. As a result, users may be denied access to voice resources (i.e., placing mobile calls) on a first-come, first-served basis. Therefore, it is appreciated that during an emergency, the assumption that a small percentage of registered users desire to place calls simultaneously becomes invalid.
Because calls may be processed on a first-come, first-served basis, first responders or other high priority users may be prevented from placing mobile calls during an emergency resulting in an inefficient allocation of voice resources. A first come, first served system for allocating voice resources may harm emergency efforts by inhibiting communications between users such as policemen, firemen, and government officials. This problem may acutely impact areas in which there are no voice resources dedicated for emergency purposes. In such areas, first responders or other high priority users typically rely on mobile networks to provide high priority communications during an emergency, yet may be unable to do so due to overwhelmed conventional voice components of mobile networks.
Accordingly, in light of these difficulties, a need exists for improved methods and systems for controlling access to mobile voice resources during an emergency or other high traffic event.